{-# LANGUAGE TypeFamilies, RankNTypes #-} -- | -- Module : Simulation.Aivika.Trans.Generator -- Copyright : Copyright (c) 2009-2017, David Sorokin -- License : BSD3 -- Maintainer : David Sorokin -- Stability : experimental -- Tested with: GHC 8.0.1 -- -- Below is defined a random number generator. -- module Simulation.Aivika.Trans.Generator (MonadGenerator(..), GeneratorType(..), DiscretePDF(..)) where import System.Random import Data.Word import Simulation.Aivika.Generator (DiscretePDF) -- | Defines a monad whithin which computation the random number generator can work. class (Functor m, Monad m) => MonadGenerator m where -- | Defines a random number generator. data Generator m :: * -- | Generate an uniform random number -- with the specified minimum and maximum. generateUniform :: Generator m -> Double -> Double -> m Double -- | Generate an uniform integer random number -- with the specified minimum and maximum. generateUniformInt :: Generator m -> Int -> Int -> m Int -- | Generate a triangular random number -- by the specified minimum, median and maximum. generateTriangular :: Generator m -> Double -> Double -> Double -> m Double -- | Generate a normal random number -- with the specified mean and deviation. generateNormal :: Generator m -> Double -> Double -> m Double -- | Generate a random number from the lognormal distribution derived -- from a normal distribution with the specified mean and deviation. generateLogNormal :: Generator m -> Double -> Double -> m Double -- | Generate a random number distributed exponentially -- with the specified mean (the reciprocal of the rate). generateExponential :: Generator m -> Double -> m Double -- | Generate the Erlang random number -- with the specified scale (the reciprocal of the rate) -- and integer shape. generateErlang :: Generator m -> Double -> Int -> m Double -- | Generate the Poisson random number with the specified mean. generatePoisson :: Generator m -> Double -> m Int -- | Generate the binomial random number -- with the specified probability and number of trials. generateBinomial :: Generator m -> Double -> Int -> m Int -- | Generate a random number from the Gamma distribution with -- the specified shape (kappa) and scale (theta, a reciprocal of the rate). -- -- The probability density for the Gamma distribution is -- -- @f x = x ** (kappa - 1) * exp (- x \/ theta) \/ theta ** kappa * Gamma kappa@ generateGamma :: Generator m -> Double -> Double -> m Double -- | Generate a random number from the Beta distribution by -- the specified shape parameters (alpha and beta). -- -- The probability density for the Beta distribution is -- -- @f x = x ** (alpha - 1) * (1 - x) ** (beta - 1) \/ B alpha beta@ generateBeta :: Generator m -> Double -> Double -> m Double -- | Generate a random number from the Weibull distribution by -- the specified shape and scale. generateWeibull :: Generator m -> Double -> Double -> m Double -- | Generate a random value from the specified discrete distribution. generateDiscrete :: forall a. Generator m -> DiscretePDF a -> m a -- | Generate a sequence number which can be considered quite unique. generateSequenceNo :: Generator m -> m Int -- | Create a new random number generator. newGenerator :: GeneratorType m -> m (Generator m) -- | Create a new random generator by the specified standard generator. newRandomGenerator :: RandomGen g => g -> m (Generator m) -- | Create a new random generator by the specified uniform generator of numbers from 0 to 1. newRandomGenerator01 :: m Double -> m (Generator m) -- | Defines a type of the random number generator. data GeneratorType m = SimpleGenerator -- ^ The simple random number generator. | SimpleGeneratorWithSeed Word32 -- ^ The simple random number generator with the specified seed. | CustomGenerator (m (Generator m)) -- ^ The custom random number generator. | CustomGenerator01 (m Double) -- ^ The custom random number generator by the specified uniform -- generator of numbers from 0 to 1.